Using a SQL Server Database File from a Class Library in C#

Question

So I have a basic 3-tier application:

Data Access
Business Logic
Presentation

My Data Access layer is a class library, and I'm using Entity Framework and a SQL Server Database File

Say my solution is structured as such

MySolution

\MySolution.Data

    \MySolution.Data\App_Data\MySolutionDB.mdf

\MySolution.BusinessLogic

\Presentation

The problem I am trying to solve is that I need to get a folder relative path to the database for the connection string because this project will not always be deployed in into the same folder structure, therefore it is imperative that the connection string is created dynamically based on the relative path.

Could someone offer some assistance on this. please?

P.S. I tried this, but it's not working:

string.Format("Data Source=(LocalDB)\v11.0;AttachDbFilename={0}\\MySolutionDB.mdf;Integrated Security=True", AppDomain.CurrentDomain.GetData("DataDirectory"))

EDIT: Getting this error message, which may be unrelated to the issue...

Connection to the database failed. The connection string is configured with an invalid LocalDB server name. This may have been set in 'global.asax' by a pre-release version of MVC4. The default connection factory is now set in web.config so the line in 'global.asax' starting with 'Database.DefaultConnectionFactory = 'should be removed. See http://go.microsoft.com/fwlink/?LinkId=243166 for details

try Environment.CurrentDirectory() + @"\App_Data\" + MySolutionDB.mdf — kd.
– kd., Commented Nov 8, 2013 at 20:40
My suggestion is to keep connection information out of the class library. Instead, set up a connection string in the app that uses it. — Dan Bracuk
– Dan Bracuk, Commented Nov 8, 2013 at 20:44
I think your are missing a \ in (LocalDB)\v11.00. I think it should be (LocalDB)\\v11.00 — Wagner DosAnjos
– Wagner DosAnjos, Commented Nov 8, 2013 at 20:50

Matthew Layton · Accepted Answer · 2014-01-03 16:45:23Z

3

Thanks to wdosanjos for pointing out my stupid mistake.

string.Format("Data Source=(LocalDB)\v11.0;AttachDbFilename={0}\\MySolutionDB.mdf;Integrated Security=True", AppDomain.CurrentDomain.GetData("DataDirectory"))

I did not escape \v11.0; it should have been \\v11.0;

edited Jan 3, 2014 at 16:45

answered Jan 3, 2014 at 16:32

Matthew Layton

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